We have some outdoor Horse Stalls that we've converted into a Ramada.   It's currently just a big pile of dirt.  We'd like to put a solid floor in in some way.   Does anyone have any advice on using something like rammed earth flooring/adobe, cob, tataki or soil concrete outdoors?  

Does anyone know contractors that do any of this in the Phoenix area?

Another thought is.. we have some massive Canary Island date palms that we plan on cutting down.  Any ideas for re-use of the palms?  We were thinking of cutting them into thick blocks and using them as pavers.  Has anyone done this?  Any thoughts on how quickly they'd decompose?

At the very least.. we could use it for a Hugelkultur garden.

Thanks!

-Trevor